BRIGHTON, CO. – DECEMBER 11: Jared Thornburg poses for a portrait at his home in Brighton, CO December 11, 2013. Thornburg was jailed 10 days for inability to pay a fine.(Photo By Craig F. Walker / The Denver Post)

It’s right there in the Colorado Constitution: “No person shall be imprisoned for debt.” And yet people in Colorado are in fact regularly imprisoned for debt when it’s owed to government in the form of minor fines.

The ACLU on Monday sent a letter to three Front Range cities — Westminster, Northglenn and Wheat Ridge — accusing them of violating the federal and state constitutions by jailing such debtors, while asking them to stop. And we hope they do, not because we have a soft spot for scofflaws who break municipal codes but because the policy is unfair and unproductive.

It’s unfair because some people genuinely can’t come up with enough money to pay even a fairly modest fine of a couple hundred dollars. And yet if they are jailed for lacking the money, they will receive a much harsher punishment for offenses such as public possession of alcohol and trespassing than do those of us who can afford to pay.

It’s no accident that both state and federal courts have frowned on such disparate treatment. They’ve said that judges can jail someone who has the ability to pay and refuses, but not someone for whom the fine is financially out of reach.

Meanwhile, the policy is unproductive because it costs taxpayers twice — first in terms of fines that are never paid but also for the food and lodging in jail.

“In contrast,” the ACLU points out, “a realistic payment plan, or a sentence of probation coupled with an order to perform community service, could actually generate a net benefit, rather than a cost, for society.”

Unfortunately, the three communities that received a letter aren’t alone. As The Denver Post’s Christopher N. Osher noted in an article Sunday, Colorado Springs, Northglenn, Fort Collins, Lakewood, Thornton, Arvada, Boulder, Loveland and Broomfield also jail people who can’t pay fines. And Denver stopped the practice only 18 months ago.

It’s as if these communities were under the impression that someone has edited the Colorado Constitution. And yet “no person shall be imprisoned for debt” still means exactly what it says.